U.S. Severe Weather Forecast (Coup d'œil sur la convection)

Day Three

acus01 kwns 010046 
Storm Prediction Center ac 010045 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0745 PM CDT Friday Oct 31 2014 

Valid 010100z - 011200z 

..no severe thunderstorm areas forecast... 

severe thunderstorms are not expected tonight. 

Downstream of the closed low now digging across the lower Ohio 
Valley...toward the southern Appalachians region...large-scale 
ascent within a residual pre-frontal axis of boundary layer heating 
appears to be aiding ongoing weak thunderstorm activity west of 
Charleston SC northward into the Charlotte NC area. As this upward 
vertical motion field pivots northeastward this evening...and 
lower-levels continue to gradually cool...thunderstorms are expected 
to begin to diminish by 03-04z time frame. 

..southern plateau/rockies region... 
Weak destabilization within a plume of relatively higher 
precipitable water roughly centered near the Arizona/New Mexico 
border is contributing to scattered ongoing weak thunderstorm 
activity. Forcing associated with a weak upper impulse which has 
migrated inland from the subtropical eastern Pacific may be 
supporting to this development...which may linger into the 03-05z 
time frame...before diminishing in response to boundary layer 
stabilization and the continued progression of the impulse to the 
northeast of the region. 

Stronger middle-level cooling in the wake of the inland advancing 
frontal zone is still expected to contribute to weak destabilization 
and a risk for thunderstorm activity overnight. Probabilities 
appear low...in general...with highest probabilities closer to the 
middle-level thermal trough axis approaching central to Southern 
California coastal areas during the 06-12z time frame. 
However...isolated thunderstorm activity does not appear out of the 
question over the San Joaquin Valley overnight. 

.Kerr.. 11/01/2014 

Mesoscale Discussion

acus11 kwns 151721 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 151720 

Mesoscale discussion 1899 
National Weather Service Storm Prediction Center Norman OK 
1220 PM CDT Wednesday Oct 15 2014 

Areas affected...central Maryland into southeastern PA 

Concerning...severe potential...watch unlikely 

Valid 151720z - 151945z 

Probability of watch issuance...20 percent 

Summary...an isolated strong wind gust or brief/weak tornado cannot 
be ruled out with storms as they develop northward from Maryland into southeastern PA. 

Discussion...an isolated strong cell with substantial vertical 
development continues to propagate northward along a north-S oriented boundary 
which extends into PA and links with an existing front across eastern PA 
which currently separates the more moist/unstable air to the southeast. 

This particular storm has had a persistent and broad circulation 
with it...but nothing particularly strong or tight probably due to 
weak low-level buoyancy/acceleration. While deep-layer flow is 
strong above the ground...most of the shear is relegated to the 
near-surface layer and other cells away from the outflow boundary 
have shown little if any shear. Therefore...any wind/tornados threat is 
expected to be brief...short-lived and isolated...and a watch is not 

.Jewell/corfidi.. 10/15/2014 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 39157664 39007677 38987688 39067699 39267696 39617690 
40007679 40347640 40457615 40407593 40137594 39617620